The heavy fire, at 19 Knowles Street, began around 5 a.m. in the rear of the three-story, wood-frame building, Yonkers Ford said, and spread to the upper floors of the three-story home.
First arriving companies found heavy fire in the rear of the building with the fire running up the rear stair case from the first floor to the third floor and extending into the cockloft, Ford said.
The fire went to a second alarm which brought roughly 50 firefighters to the scene.
All companies made an aggressive attack from the interior and had the fire under control in roughly one hour.
Five firefighters were treated for minor injuries, and one resident was transported to St Joseph's Medical Center for difficulty breathing.
The 15 residents, none of whom were injured, are being relocated by the Red Cross until the owners can repair damage to the back steps and porches.
Three of the six apartments were under renovation and vacant at this time, or more people would have been displaced, Ford said.
The cause and origin of the fire are still under investigation by the Yonkers Fire Investigation Unit and the YPD Detective Division
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